prutton



Aug. 18, 1959 D. H. PRUTTON MOVABLE DIE MOUNTING 2 Shgets-Sheet 1 Filed Oct. 13 1954 INVENTOR.

ATTORNEYS Daniel Howard Prutfon BY gm/ hg dw, fi/Md 4927M Aug. 18, 1959 D. H. PRUTTON MOVABLE DIE MOUNTING 2 Sheets-Sheet 2 Filed Oct. 13. 1954 m a wwm ,H

1 w. l l L Fig. 4

IN V EN TOR.

as mi flaw M v a A W wwfl W United States Patent Patented Aug. 18, 1959 fiice This invention relates to a die having a contour surface thereon for rolling forms on workpieces and more particularly to a yieldable support for said surface.

One of the objects of the present invention is to provide a die means for a machine adapted to roll a form on a workpiece wherein the forming surface of said die is yieldably mounted for permitting separating movement with respect to its coacting die surface upon application of an abnormal force thereto by the workpiece wherein this force is caused by variations in dimensions of the die forming surface and/or the workpiece.

A further object of the present invention is to provide a die means of the character described that will assure that the contoured surface on all finished workpieces will be uniform in appearance even though the rolling surface on the die and the workpieces may vary in dimensions.

Other features of this invention reside in the arrangement and design of the parts for carrying out their appropriate functions.

Other objects and advantages of this invention will be apparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings,

Fig. 1 is a top plan view of a machine for roll-forming workpieces with the present invention utilized therein;

Fig. 2 is a top plan view of one of the die blocks thereon with a portion thereof shown in horizontal sectional view;

Fig. 3 is a vertical sectional view taken along the line 33 of Fig. 2; while Fig. 4 is a vertical sectional view taken along the line 4-4 of Fig. 2.

Before the die block here illustrated is specifically described, it is to be understood that the invention here involved is not limited to the structural details or arrangement of parts here shown since die blocks embodying the present invention may take various forms. It also is to be understood that the phraseology or terminology herein employed is for purposes of description and not of limitation since the scope of the present invention is denoted by the appended claims.

While this invention might be adapted for use on various types of machines, I have chosen to show the same as applied to that disclosed in my copending US. patent application, Serial No. 409,911, filed February 12, 1954, and entitled Machine for Thread Rolling to which further reference may be had for additional disclosure, if necessary.

This machine has a frame, base or table having a flat top surface on which are mounted first and second die means having generally complementary contour rolling surfaces thereon for rolling the contour surface on the workpieces. The first or inner die means includes die ring 12 having a generally circular periphery with contour rolling surfaces 12a thereon. This die ring 12 has a' bore with a conical surface complementary to the 1 frame.

periphery of a hub 14 to which it is detachably secured by a plurality of circumferentially spaced bolts 15. This hub 14 is secured to a spindle 13 rotatably mounted on frame 10.

A second or outer die means is also provided on the One or more (only two being shown in Fig. 1) back stop blocks 17 are detachably or permanently secured to frame 10 so as to be normally rigid therewith during machine operation. Each carries a die block 18 detachably mounting a die 20 therein with the latter having a contour rolling surface 20a thereon complementary to and located outwardly from contour rolling surface 12a on die ring 12.

These dies 12 and 20 are operatively connected so that one moves relative to the other while the machine is operating. In the present disclosure, die ring 12 is rotated past the relatively stationary dies 20 by a motor or any other suitable drive rotating shaft 13. As this relative movement occurs, workpieces or blanks, preferably having a cylindrical outer surface, are introduced between the dies so as the surfaces 12a and 20a move relative to each other they frictionally engage successively the workpieces and roll a contour form thereon. This may take the form of screw threads or any other desired contour form. This form may be generated on any cylindrical surface (circular in cross section) whether a true cylinder of uniform diameter or a slightly tapered surface. The present invention is also applicable whether an outer cylindrical surface is being roll formed, as shown in the drawings, or an inner cylindrical surface, is being correspondingly manufactured.

Problems have occurred during operation when both the vertical, central axis of spindle 13 and dies 20 are fixed against horizontal movement with respect to the frame 10 so that the space between the contoured surfaces 12a, 20a always remains substantially constant. If the space between these surfaces is not proper for satisfactory rolling operation, problems occur. For example, any variation in dimensions of either the die or the workpiece will cause difficulty. First, the dimensional variations in the dies will be considered. The dies are frequently finished and then hardened. If hardening causes run-out in the formed surface on the die, a variation in this critical spacing will occur. Second, if the blank or workpiece is oversized, out of round, eccentric or burred, not only the contour rolled thereon may be distorted but also one or both of the die surfaces may be badly mutilated so that replacement is necessary.

Each die block 18 includes a base 30 in Fig. 4 detachably connected to the frame 10 and adapted to be rigidly held thereto during machine operation. Base 30 is of generally L-shape and includes interconnected vertical and horizontal sections 30a, 3191) respectively here shown as forming an integral base. This base 30 is held down on the top of table or frame 10 by two bolt down screws or tightening bolts 31, 31 by having the threads on each bolt 31 screwed into base 10 so that its head in Fig. 3'

pulls down base section 3% against frame 10 by the washer 33, bushing 32 and bushing shoulder 32a pressing down against the top surface of the horizontal base section 30b. The shank of each bolt 31 in Fig. 2 is spaced from the bore of its surrounding bushing 32 to permit horizontal adjustment of block and die positions in four different directions before firmly tightening bolts 31.

Also, abutment bolts 35 in Figs. 1 and 2 are screwed into and protrude from each associated back stop block 17 to serve both in withstanding the stresses from the form rolling operation and in effecting positional adjustment of die holding block 18 before bolts 31 are tightened down. 2

Die block 18 includes a slide supported in Fig. 4 by horizontal base section 3% and back stopped against horizontal movement by vertical base section 30:: in the present disclosure. This slide includes a slide body 38 having a mounting or clamping means for detachably connecting thereto associated die 20. This includes top and side die clamp fingers 39, 40 pulled up into tightening position by clamp screws 41, 42 respectively. The side clamp finger 40 forms a dove-tailed construction with slide body 38 and die 20 in the manner shown in Fig. 2. Top clamp finger 39 clamps die 20 downwardly in Fig. 4 against spacer 44 resting on a forwardly protruding shoulder in slide body 38. Top clamp finger 39 in Fig. 2 has an elongated slot therein permitting endwise adjustment of its clamping position. Hence, die 20 may be easily removed from slide body 38 by loosening screws 41, 42 for replacement by another die having the same or a different contour form thereon.

Slide body 38 and base 30 are provided with keying means restricting movement of the slide to a generally straight line movement in the present disclosure generally parallel to the top surface of horizontal base section 30b and perpendicular to the backstop surface provided by vertical base section 30a. This relative movement is generally radial to ring die 12. In the present disclosure, holes in slide body 38, surrounding bushings 32, have sufficient looseness to permit relative movement between slide body 38 and base 30 while washers 33 in Fig. 3 restricts this movement to be generally parallel to the top surface of horizontal base section 30b. Key 45 in Fig. 3 is a press fit in base section 301; and a slip fit in a keyway of slide body 38 so as to restrict horizontal movement of slide body 38 to a generally straight line movement of a radial nature and generally perpendicular to the backstop surface of vertical base section 300.

Yieldable means, taking the form in the present disclosure of a resilient rubber backup pad or cushion 48 in Figs. 2 and 4, permits separating movement between die surfaces 12a, 20a from the normal position shown in Fig. 1 upon application of an abnormal force thereto by the workpiece being formed since cushion 48 can be compressed. Upon removal of this abnormal force, the re siliency of rubber cushion 48 returns die surface 20a back to its normal position by the urging force of its resiliency. This pad or cushion 48 is shown as being located between slide body 38 and the abutment surface on vertical body section 30a. However, it should be understood that rubber material, other suitable resilient means, or other suitable yieldable means and returning means could be provided to connect either die surface 12a or 20a to frame to permit relative movement therebetween in response to abnormal forces. For example, slide body 38 may be constructed with clearance with respect to only one bushing 32 while pivoting around the other hold-down bolt 31 so as to provide this relative movement, but this construction might cause jamming at the pivoting end of die because of the lack of radial movement thereat. Also, a rubber sleeve could be provided around one or both bolts 31 to serve as the resilient, yieldable means, but then the adjustability provided by the clearance between such bolts 31 and the bore of bushing 32 would not be obtained. However, the illustrated construction is the preferred construction because of its many advantages.

Hence, this construction with resilient rubber pad 48 permits separation between die surfaces 12a, 20a upon application of an abnormal force thereto caused by variations in die and workpiece dimensions and then returns surface 20a back to its normal position upon removal of the abnormal force. These variations may occur in the die if it is distorted during hardening to cause run-out or in the workpiece if it is oversized, out of round, eccentric, burred, etc. This relative movement between the die surfaces is especially desirable in manufacturing parts wherein uniformity of appearance is important for sales reasons, wherein holding a close tolerance on the size of the workpiece or blank is not economically feasible, and wherein economy in manufacture is a primary consideration rather than close tolerances on the size and shape of the finished rolled form. For example, wood screws, sheet metal screws, drive nails having a formed surface on their shanks, etc. may be manufactured at minimum cost and at maximum uniformity in appearance. Also, the life of dies 12 and 20 is considerably extended since abnormal forces have not been permitted to be exerted thereon and no jamming can occur in the machine.

it should be apparent that die blocks 18 in Fig. 1 may be easily substituted for the corresponding die blocks on the machine disclosed in said copending application and, after suitable modification, on any other type contour or thread rolling machine.

In the present construction, dies 20 are easily removed and interchanged for dies with the same or different roll forms thereon during setup. Also, the many adjustable features make it possible to closely adjust the position of dies 20 during machine setup.

Various changes in details and arrangement of parts can be made by one skilled in the art without departing from either the spirit of this invention or the scope of the appended claims.

What I claim is:

1. Apparatus for rolling forms on generally cylindrical surfaces of workpieces comprising a frame, a first die means rotatably mounted on said frame and having a generally circular periphery with a contour rolling surface thereon, a second die means located on said frame and including an outer die having a contour rolling surface thereon complementary to and located outwardly from the rolling surface on said first die means, means operatively connecting said first die means to said frame for rotating said first die means surface relative to the other to frictionally engage a workpiece and roll a contour form thereon; said second die means including a base adjustable relative to said frame toward and away from said first die means, a slide movably supported by said base and detachably carrying said outer die, a single connecting means clamping together said base and frame in any given adjusted position and forming a lost motion connection between said slide and base, and resilient means biasing said slide relative to said base against one end of said lost motion connection wherein said contour rolling die surfaces are closest together.

2. Apparatus for rolling forms on generally cylindrical surfaces of workpieces comprising a frame, a first die means rotatably mounted on said frame and having a generally circular periphery with a contour rolling surface thereon, a second die means located on said frame and including an outer die having a contour rolling surface thereon complementary to and located outwardly from the rolling surface on said first die means, means operatively connecting said first die means to said frame for rotating said first die means surface relative to the other to frictionally engage a workpiece and roll a contour form thereon; said second die means including a base adjustable relative to said frame toward and away from said first die means, a slide movably supported by said base and detachably carrying said outer die, a single connecting means clamping together said base and frame in any given adjusted position and forming a lost motion connection between said slide and base, and resilient means biasing said slide relative to said base against one end of said lost motion connection wherein said surfaces are closest together, said single connecting means including a bushing telescoped through an enlarged hole in said slide to form said lost motion connection and having one end bearing against said base, and including means extending through said bushing and base for urging the bushing against said base to secure the base at any adjusted position to said frame.

3. Apparatus for rolling forms on generally cyclindrical surfaces of workpieces comprising, a frame, a first die tic-L; v

means rotatably mounted on said frame and having a generally circular periphery with a contour rolling surface thereon, a second die means located on said frame and having a contour rolling surface thereon complementary to and located outwardly from the rolling surface on said first die means, and means operatively connecting said first die means to said frame for rotating said first die means surface relative to the other to frictionally engage a workpiece and roll a contour form thereon; said second die means including interconnected horizontal and vertical sections forming a generally L-shaped base, means for adjustably moving said base toward and away from said first die means during set up, a slide supported by the horizontal section and back stopped against horizontal movement by the vertical section of said L-shape, said slide having clamping means detachably connecting thereto a die having said form rolling surface of said second die means thereon, keying means on said slide and base restricting movement of said slide to movement generally parallel to said horizontal section and perpendicular to said normal position upon removal of said abnormal force, a connecting means clamping together said base and frame in any given adjusted position and forming a lost motion connection between said slide and base with said rubber pad biasing said slide relative to said base against one end of said lost motion connection wherein said surfaces are closest together, said single connecting means comprising a pair of spaced apart connecting units straddling said keying means with each unit including a bushing telescoped through an enlarged hole in said slide to form said lost motion connection and having one end bearing against said base, and including means extending through said bushing and base for urging the bushing against said base to secure the base at any adjusted position to said frame.

References Cited in the file of this patent UNITED STATES PATENTS 284,633 Harvey Sept. 11, 1883 470,805 Jones Mar. 15, 1892 780,527 Replogle et a1. Jan. 24, 1905 1,414,668 Reed May 2, 1922 1,699,033 Smith Jan. 15, 1929 2,289,524 Smith et a1 July 19, 1942 2,587,132 Finke Feb. 26, 1952 

